In an injection blow molding machine known from DE 197 37 697 A, two injection molding rotors are associated with the transfer rotor, said injection molding rotors being supplied with plasticized plastic material by a common extruder and comprising each a plurality of individual mold cavities. The total number of mold cavities in the two injection molding rotors corresponds to the number of blow molds on the blow molding rotor. One of the injection molding rotors is rotatingly driven, whereas the other is stationary. In the stationary injection molding rotor, the preforms are injection molded, whereas the rotating other injection molding rotor transfers the finished preforms one by one via the transfer rotor to the blow molding rotor. Prior to being transferred, the preforms are cooled in the injection molding rotor. The temperature or temperature distribution in each preform can be conditioned by tempering prior to the blow molding process. In the one-stage process carried out in the injection blow molding machine, the blow molding cycle time is substantially shorter than the cycle time required for producing and tempering the preform. Since the total number of mold cavities corresponds to the number of injection molds, it is difficult to optimally use the capacity of the blow molding rotor. In addition, a high amount of energy is required for the subsequent conditioning of the preforms.
In an injection blow molding machine known from DE 31 24 523 C, a central injection molding rotor, which comprises a plurality of mold cavity groups and which is supplied by a single extruder, has peripherally associated therewith a total number of four blow molding rotors for stretch blow molding the containers in groups.
U.S. Pat. No. 3,357,046 A discloses that stationary blow molds have associated therewith a rotating extruder arrangement, that the preforms are formed by severing them from a tube portion, and that they are filled immediately with the future container content and formed into containers.
In the injection blow molding machine known from DE 195 28 695 A, two injection molding units, which each comprise a plurality of mold cavities, are movable relative to injection molding cylinders in an injection molding station. The preform groups are removed from the mold cavities in the direction of their longitudinal axes and are then transferred in a direction transversely to the blow mold groups. The preform group can be transferred to and introduced in the blow mold group with a transfer tool comprising a plurality of neck molding parts, or the transfer tool is replaced, between the injection molding unit and the blow mold groups, by another blow-mold neck molding tool for dealing with a plurality of preforms simultaneously. The finished containers are removed from the neck molding tools and transported away.